Former Bosnian Serb leader Radovan Karadzic, a war crimes fugitive and one of the world's most wanted men, was arrested on Monday evening in a sweep by Serbian security forces, the country's president said. Karadzic was indicted by the UN war crimes tribunal for the former Yugoslavia for genocide during the 1992-95 Bosnian war. He had been in hiding since 1998. President Boris Tadic's office said in a statement that Karadzic was arrested "in an action by the Serbian security services." Karadzic, who was the leader of ethnic Serbs during the war that erupted with Bosnia's secession from Yugoslavia, is accused of masterminding massacres that the UN war crimes tribunal described as "scenes from hell, written on the darkest pages of human history." He had topped the tribunal's most-wanted list for more than a decade and was said to have resorted to elaborate disguises to elude authorities.